The pump in question is EK 4.0 3pin Pump
Prior to upgrading to my Crosshair V Formula, I was using this pump flawlessly on my old MSI 870A motherboard and the bios settings were able to control the pump speed with no problems.
I installed the crosshair and here is what started happening...
1. I had the pump installed via the 4 pin molex adapter and everything was great. Setup some of the chassis fans to be controlled by Fan Xpert and life was good.
2. I got unhappy with how loud the pump was at 12v so I decided to plug the pump in to CHA_FAN 1 header and noticed that the pump was not slowing down even though I the software said it was controlling it.
3. Plugged back in my NZXT 3 pin fan into CHA_FAN 1 and noticed that it is no longer slowing down and speeding up with the software anymore.
4. Checked to make sure that CHA_FAN2 was throttling the fans as intended and sure enough it is, so I unplug the fan and plug in the pump, boot the system and once again, pump running at 100% and not slowing down.
5. I turn off the system and plug the fan back in to CHA_FAN 2 and boot up the system and notice once again that now neither CHA_FAN1 OR 2 are slowing down the fans...
6. I did the same thing with CHA_FAN3, double checked that it slows down with Fan Xpert and as expected they are, but after plugging in the pump to CHA_FAN3, it no longer slows down the fans when switched back.
NOW... I have my 3 radiator fans being controlled by OPT FAN 1 with Duty cycle of 60% and the fans are slowing down PERFECTLY, but I refuse to plug my pump in for fear that it will somehow mess up the controller for the OPT 3 pin plugs next.
ASUS, whats going on?? Why can my $100 MSI-870A control my pump just fine, with 0 issues, but the second its plugged in to one of these plugs on my ASUS Crosshair V Formula, all software control ceases to work?
Unless someone from ASUS support knows what is going on, my next step is going to be to request an RMA and get this thing replaced, one of the REASONS I bought this mobo to begin with is due to the 8 fan headers that allow me to not have to have a fan controller installed.
Please ask your techs if there is some sort of a reset for the controller, because once my pump was plugged in, everything went to 100% and never came back.
Here are things I did to remedy...
1. Updated to the latest bios. I was still on an older bios from the factory
2. Reset the BIOS
3. Tried the UEFI settings to control the fans, but just as mentioned with Fan Xpert, bios fan settings have 0 effect on the 3 CHA fans
How on earth can a pump rated 1.5A 18w cause this to happen with fan headers rated at 24 watts??
This is straight from the manual
"The fan connectors support cooling fans of 350 mA-2000mA (24 W max.) or a total of 1 A -7 A (84 W max.) at +12V. Connect the fan cables to the fan connectors on the motherboard , ensuring that the black wire of each cable matches the ground pin of the connector."
Based on that, this pump is well within the technical specs of the fan headers, not to mention if this pump had an issue with it, I would assume that the headers would fail, not run 100% at all times...
I forgot to mention that I bought this board in the begining of March, so it is only a month and half old.